Competitive effects of compounding aromatic hydrogen storage carriers in low-pressure hydrogenation reactions

The reaction activity of various liquid organic hydrogen carriers (LOHCs) over 5 wt% Rh/C (BET surface area 933.5 g/cm 3 , pore size 4.6 nm, metal dispersion 10.5 %) and 5 wt% Ru/C (BET surface area 888.4 g/cm 3 , pore size 6.1 nm, metal dispersion 8.9 %) catalysts is evaluated. The results show that monocyclic aromatic hydrocarbons have the highest reactivity, followed by monocyclic aromatic rings, while polycyclic and fused cyclic aromatic hydrocarbons have relatively low activity. It is also found that mixing different LOHCs leads to a competitive effect, resulting in lower reactivities for all LOHCs. As the degree of LOHC hydrogenation increases, the adsorption of multi-step hydrogenation intermediates becomes more difficult, resulting in lower yields of fully hydrogenated products. It is important to understand the behavior of LOHCs in hydrogenation reactions and to optimize the performance of LOHCs compound systems. • The compounding of different LOHCs tend to occur a strong competition. • The adsorption of LOHCs on catalysts dominates the result of competition. • LOHCs with high adsorption energy are harder to get totally hydrogenated.